#define _CRT_SECURE_NO_WARNINGS 1

#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
#include <iomanip> 

using namespace std;

struct Point {
    double x, y;
};

double calculateRadius(vector<Point>& points) {
    double maxDistance = 0.0;

    for (int i = 0; i < points.size(); ++i) {
        for (int j = i + 1; j < points.size(); ++j) {
            double distance = hypot(points[i].x - points[j].x, points[i].y - points[j].y);
            maxDistance = max(maxDistance, distance);
        }
    }

    return maxDistance / 2;
}

int main() {
    int N;
    while (cin >> N && N != 0) {
        vector<Point> points(N);
        for (int i = 0; i < N; ++i) {
            cin >> points[i].x >> points[i].y;
        }

        double radius = calculateRadius(points);
        cout << fixed << setprecision(2) << radius << endl;
    }

    return 0;
}